Molten metal filtration improves casting quality and machinability

Filtering molten metal, especially ductile iron, steel, and aluminum, results in better mechanical properties and reduced machining tool wear. Over the last 10 years, ceramic filters have proven themselves effective in producing cleaner castings by removing inclusions that can adversely affect ductility, fatigue resistance, and toughness. They have also been shown to allow increased pouring rates and lower pouring temperatures in commercial foundry operations. This article reports results of a filtration study conducted by Caterpillar Inc., Mapleton, Ill. Work done by Corning Glass in developing filters for steel casting operations indicates that extruded cellular mullite filters, with between 50 and 200 cells per square inch, provide effective contaminant removal.